AI-Based Discovery and CryoEM Structural Elucidation of a KATPChannel Pharmacochaperone

Abstract

AbstractPancreatic KATPchannel trafficking defects underlie congenital hyperinsulinism (CHI) cases unresponsive to the KATPchannel opener diazoxide, the mainstay medical therapy for CHI. Current clinically used KATPchannel inhibitors have been shown to act as pharmacochaperones and restore surface expression of trafficking mutants; however, their therapeutic utility for KATPtrafficking impaired CHI is hindered by high-affinity binding, which limits functional recovery of rescued channels. Recent structural studies of KATPchannels employing cryo-electron microscopy (cryoEM) have revealed a promiscuous pocket where several known KATPpharmacochaperones bind. The structural knowledge provides a framework for discovering KATPchannel pharmacochaperones with desired reversible inhibitory effects to permit functional recovery of rescued channels. Using an AI-based virtual screening technology AtomNet® followed by functional validation, we identified a novel compound, termed Aekatperone, which exhibits chaperoning effects on KATPchannel trafficking mutations. Aekatperone reversibly inhibits KATPchannel activity with a half-maximal inhibitory concentration (IC50) ~ 9 μM. Mutant channels rescued to the cell surface by Aekatperone showed functional recovery upon washout of the compound. CryoEM structure of KATPbound to Aekatperone revealed distinct binding features compared to known high affinity inhibitor pharmacochaperones. Our findings unveil a KATPpharmacochaperone enabling functional recovery of rescued channels as a promising therapeutic for CHI caused by KATPtrafficking defects.